This is comparing apples to oranges....or maybe Jonathan apples to Golden Delicious. Either are great, but you can't really compare flavors since they have inherent differences peculiar to the variety.
The Asrock board is an mITX board that is designed for compact cases while the Tomahawk is a full size ATX board and will be best used in a large case with good airflow. Because it's designed to go into tiny cases the ITX board has inherent compromises to limit heat output and maintain stability, and usually carries a price premium to boot. That means you may have limited overclocking potential which is one thing the Tomahawk is noted for, with big and effective heatsinking on an over-designed (for a 4 phase) VRM with a lot of FET's to carry the load.
Part of the price premium comes from built-in WiFi on the Asrock, a desireable feature for compact mITX systems.
All that said, a 2200G, with a 4 core CPU, isn't going to present a heavy load on the VCore VRM. But being an APU the GPU loves super-fast memory and either board should deliver with a good high-speed, low latency DIMM kit installed.
I'd say either board would work well but if your looking at a full-size case just go for the Tomahawk as it should be available for a bit cheaper too. Unless you really need Wifi and don't have a WiFi add-in card to go into the Tomahawk.